The proposal focuses on how listeners accommodate variability in the speech signal during spoken word recognition. We focus on two dimensions of systematic variability, co-articulatory information and phonological variation. Phonological variants of a word are hypothesized to be explicitly represented (pre-compiled) in lexical representations and includes a linkage between alternative forms that is excitatory and variant frequency sensitive. Co-articulatory information is investigated with regard to its role in activating and maintaining lexical representations. The goal is to understand how potentially constraining sources of linguistic knowledge (form frequency, acoustic-phonetic similarity and sequential structure) are coordinated with systematic variation to generate and confirm lexical hypotheses.